Various types of medical infusion pumps are known in the art. One common type of infusion pump is a peristaltic pump, in which fluid is made to flow through an elastic tube by external compression of the tube. Typically, a peristaltic mechanism, such as a set of cams or fingers, compresses the tube in a cyclic pattern at a sequence of locations along the length of the tube, so as to cause the fluid to flow through the tube at a desired volumetric rate. Peristaltic infusion pumps are described, for example, in U.S. Pat. Nos. 5,290,158, 5,395,320, and 5,807,322, as well as in U.S. Patent Application Publications 2007/0269324 and 2009/0221964. The disclosures of all of these cited patents and publications are incorporated herein by reference.